14 research outputs found
Persistent Toxic Burdens of Halogenated Phenolic Compounds in Humans and Wildlife
Halogenated phenolic compounds (HPCs)
including hydroxylated polychlorobiphenyls
(OH-PCBs) and hydroxylated polybromodiphenyl-ethers (OH-PBDEs) can
be persistent organic pollutant (POP) metabolites or natural marine
compounds. Structurally similar to thyroid hormones (THs), they are
retained in blood, transported through selective barriers, and the
cause of endocrine and neuronal POP effects. This study presents a
meta-analysis of HPC burdens in human and wildlife tissues, including
OH-PCBs, OH-PBDEs, Pentachlorophenol, and polybromophenols. HPC blood
plasma levels were also compared to known <i>in vitro</i> and <i>in vivo</i> toxicological effect concentrations.
Blood, highly perfused, and fetal tissues contained the highest levels
of HPCs. Plasma concentrations of analyzed OH-PCBs/PBDEs ranged from
0.1 to 100 nM in humans and up to 240, 454, 800, and 7650 nM for birds,
fish, cetaceans, and other mammals, respectively. These concentrations
fully fall within the <i>in vitro</i> effect concentrations
reported in literature for HPCs of 0.05â10000 nM. We strongly
advise further study of HPC blood levels in the general population,
children, and fetal tissue to establish background levels and the
risk at sensitive development stages. As not all HPCs are, or can
be, chemically analyzed, the application of additional bioanalysis
might reveal an even greater toxicological relevance of HPCs. In addition,
metabolic activation should always be included within <i>in vitro</i> hazard assessment of POPs
Protecting the child while preserving the relationship: Using babyâs relational withdrawal to gauge the effect of parental visitation
<div><p>The impact of childrenâs interactions with parents in the context of out-of-home placements is receiving much-needed cross-disciplinary attention. However, the paucity of instruments that can reliably represent young childrenâs experiences of such interactions precludes a nuanced evaluation of their impact on wellbeing and development. In response to this empirical gap, the present study investigates childrenâs relational withdrawal as a clinically salient, easily observable and conceptually valid measure of infantsâ and toddlersâ responses to parents. Relational withdrawal, challenging behaviors and salivary cortisol were assessed before, during and after parental visits. Conceptually, the findings suggest that observations of relational withdrawal correlate meaningfully with measure of neurobiological reactivity. Clinically, three profiles of cross-variable responses in children appeared, distinguishing between groups that experience increased, decreased or unchanged levels of stress in response to parental visits. Taken together, the findings lend empirical support to systematic observations of relational withdrawal to bolster evaluations of young childrenâs experience of parental visitation during out-of-home placements.</p></div
Differently Environment Stable Bio-Silver Nanoparticles: Study on Their Optical Enhancing and Antibacterial Properties
<div><p>Generally, limited research is extended in studying stability and applicational properties of silver nanoparticles (Ag NPs) synthesized by adopting âgreen chemistryâ protocol. In this work, we report on the synthesis of stable Ag NPs using plant-derived materials such as leaf extract of Neem (<i>Azadirachta indica</i>) and biopolymer pectin from apple peel. In addition, the applicational properties of Ag NPs such as surface-enhanced Raman scattering (SERS) and antibacterial efficiencies were also investigated. As-synthesized nanoparticles (NPs) were characterized using various instrumentation techniques. Both the plant materials (leaf extract and biopolymer) favored the synthesis of well-defined NPs capped with biomaterials. The NPs were spherical in shape with an average particle size between 14-27 nm. These bio-NPs exhibited colloidal stability in most of the suspended solutions such as water, electrolyte solutions (NaCl; NaNO<sub>3</sub>), biological solution (bovine serum albumin), and in different pH solutions (pH 7; 9) for a reasonable time period of 120 hrs. Both the bio-NPs were observed to be SERS active through displaying intrinsic SERS signals of the Raman probe molecule (Nile blue A). The NPs were effective against the <i>Escherichia coli</i> bacterium when tested in nutrient broth and agar medium. Scanning and high-resolution transmission electron microscopy (SEM and HRTEM) images confirmed cellular membrane damage of nanoparticle treated <i>E. coli</i> cells. These environmental friendly template Ag NPs can be used as an antimicrobial agent and also for SERS based analytical applications.</p> </div
Estimated marginal means of salivary cortisol by group of relational withdrawal.
<p>Estimated marginal means of salivary cortisol by group of relational withdrawal.</p
Estimated marginal means of salivary cortisol as a function of reaction profile (interaction).
<p>Estimated marginal means of salivary cortisol as a function of reaction profile (interaction).</p
Colloidal stability of <i>A. indica</i> Ag NPs in different media.
<p>Time dependent UV-Vis absorbance spectra and zeta (HDD and ζ potential value) measurements of <i>A. indica</i> Ag NPs dispersed in different media. <i>A. indica</i> Ag NPs dispersed in (a-b; e-f) NaCl, (c-d; g-h) NaNO<sub>3</sub>, (i-j; m-n) BSA, (k; o) pH 7 and (l; p) pH 9.</p
Estimated marginal means (logarithmic) for reaction profiles and repeated measures ADBB scores including age and duration of placement as covariates.
<p>Estimated marginal means (logarithmic) for reaction profiles and repeated measures ADBB scores including age and duration of placement as covariates.</p
Electron microscopy images of bio-Ag NPs exposed <i>E. coli</i> cells.
<p>SEM images of <i>E. coli</i> cells treated with (a-c) <i>A. indica</i> Ag NPs and (d-f) pectin Ag NPs. HRTEM images <i>E. coli</i> cells treated with (g-i) <i>A. indica</i> Ag NPs and (j-l) pectin Ag NPs.</p
Colloidal stability of bio-silver nanoparticles in water.
<p>(a) UV-Vis absorbance spectra, and (b) HDD and ζ potential values of <i>A. indica</i> Ag NPs. (c) UV-Vis absorbance spectra and (d) HDD and ζ potential values pectin Ag NPs.</p